An AR technology has been prevailing which superimposes and displays CG generated by a computer over the real word or an image that reflects the real world. CG is an abbreviation of computer graphics and AR is an abbreviation of augmented reality.
For example, a method is available which projects CG from a projector over a building existing in a direction in which the user faces. Also, a method is available which superimposes and displays CG when an image photographed by a camera provided to an information terminal such as a smart phone, a tablet-type terminal, or a wearable terminal is to be displayed on the screen of the information terminal.
These techniques can be used in usages such as a tourist assistance system which displays information explaining a neighboring building to a tourist and a navigation system which displays a route to a destination by CG.
When CG is superimposed and displayed over the real world, part of the real world existing in the portion where the CG is superimposed and displayed cannot be seen or is difficult to see. This situation will not pose a problem if the real world corresponding to the CG superimposed portion need not be seen, but will become an issue in terms of usability if the real world is to be seen.
A display device which transmits information useful to the user exists in the real word, other than an information processing terminal which superimposes and displays CG by the AR technology. Therefore, if CG is superimposed and displayed over a portion where a display device is displayed, information transmitted by the display device will be blocked, and the profit of the user will be impaired.
Patent Literature 1 discloses a technique which, by specifying a CG excluding area where CG will not be superimposed and displayed, prevents CG from being superimposed and displayed over the CG excluding area.
Note that the user must clearly specify the CG excluding area by using a CG excluding frame or an electronic pen, or with his or her own hands.
This requires a labor for adjusting the position and size of the CG excluding area. Also, as the CG will not be superimposed and displayed on the CG excluding area, the CG to be superimposed and displayed is likely to be missed partly. If the CG excluding area is larger than needed, it is likely that the CG is not displayed at all. As a result, information will not be transmitted effectively.
When CG is superimposed and displayed on the display device, it is difficult for the user to recognize information displayed on the display device.